We now learn that prior to the arrests of nine men in Birmingham last February for an alleged plot to behead a British Muslim soldier, "journalists on at least one tabloid paper were tipped off the night before the raids, with the result that some travelled there before anyone had been arrested".

"On the morning of the arrests, almost before the detainees had arrived at the police stations to which they were being taken for questioning, it was clear that key details of the investigation and the evidence had been leaked. This damaged the interview strategy of the investigators, and undoubtedly raised community tensions. I have no idea where the leaks came from, but whoever was responsible should be thoroughly ashamed of themselves."

At the time, the Daily Mail, for example, left little doubt as to who was behind the alleged Birmingham plot: Al-Qaida Was Behind Plot To Behead Soldier. Note the absence of any quotation marks around the headline, thereby indicating, in the view of the paper, that this was a statement of fact, not conjecture.

Who did the leaking? Today's newspapers claim that a close aide to the Home Secretary, John Reid, is implicated along with a senior Scotland Yard figure. There were rumours at the time that news had been leaked to divert attention from problems in Whitehall.

I personally have no idea whether the six Birmingham men who were subsequently charged with a number of terrorism offences committed or planned to commit a crime. However, whether they did or did not, we should all find out via the the normal legal route. This is not to seek special treatment for Muslims accused of crimes. It is simply to help ensure that all of us be allowed a level playing field on which to conduct any defence.

This whole episode raises the unpleasant and disturbing spectre of law enforcement agencies being used for political purposes and the rights of citizens being sacrificed at the altar of political expediency.

If law enforcement activities are carried out with the prior knowledge of favoured sections of the media, then the motivation for such actions are bound to be questioned and it is inevitable that public confidence, so essential an element in successful policing, will be undermined.

The prime minister was surely wrong yesterday when he refused to establish an independent leak inquiry. Public confidence in the integrity of our law enforcement agencies must be maintained and if confidential information has been unlawfully disclosed then prosecutions should follow.